Lithium-ion secondary battery has features that the energy density is higher than other secondary batteries and operation at high-pressure is feasible. Therefore, it is used as a secondary battery which is capable of reducing its size and weight for information equipment such as cellular phone. Recently, demand of lithium-ion secondary battery for a power source of large-sized apparatus such as hybrid car is increasing.
The lithium-ion secondary battery comprises: a cathode layer; an anode layer; and an electrolyte disposed therebetween, wherein the electrolyte is composed of nonaqueous liquid or solid substances. When a nonaqueous liquid (hereinafter, refer to as “electrolytic solution”.) is used as the electrolyte, the electrolytic solution permeates inside the cathode layer. So, interface with an electrolyte and a cathode active material constituting the cathode layer is easily formed, thereby the performance of the battery can be easily improved. However, widely used electrolytic solution is flammable so that it is necessary to mount a system to secure its safeness. On the other hand, solid electrolyte is nonflammable; thereby the above system can be simplified. Hence, a lithium-ion secondary battery having a mode which comprises a nonflammable solid electrolyte (hereinafter, refer to as “solid electrolyte layer”.) has been proposed.
In the case of lithium-ion secondary battery (hereinafter, refer to as “compact all-solid-state battery”.) in which a solid electrolyte layer is disposed between a cathode layer and an anode layer, since the cathode active material and the electrolyte are solid, the electrolyte is hard to be permeated inside the cathode active material; whereby interface between the cathode active material and the electrolyte tends to decrease. Therefore, in the case of compact all-solid-state battery, by using, as a cathode layer, a cathode mixture layer containing a mixed powder having a powder of cathode active material and a-powder of solid electrolyte, area of the interface has been increased.
As an art related to secondary battery, for example, Patent document 1 discloses a battery comprising: a separator for battery having a-pleated-sheet structure; a group of electrodes, wherein a plurality of the electrodes (cathode or anode) are disposed in each of the recessed portion on one side of the separator and other electrodes (anode or cathode) are disposed in each of the recessed portion on the opposite side of the separator. In addition, Patent document 2 discloses a sheet-type battery, wherein a plurality of cathode sheet having a sheet-type cathode current collector to which a cathode active material is applied and a plurality of anode sheet having a sheet-type anode current collector to which an anode active material is applied are laminated alternately across a separator or a solid electrolyte layer, wherein the separator or the solid electrolyte layer are bent in a zig-zag manner as if the separator or the solid electrolyte layer is to thread its way through the cathode sheets and anode sheets. Moreover, Patent document 3 discloses a rectangular battery, in which a plurality of sheet-type positive plates and negative plates are respectively facing and alternately superposed through a separator, wherein at least positive plates or negative plates are successively packaged by a substantially tape-shape separator and folded along the fusion-bonding part of the separators between the electrode plates.
Patent Document 1: Japanese Patent Application Laid-Open (JP-A) No. 2002-157990    Patent Document 2: JP-A No. 2002-329530    Patent Document 3: JP-A No. 07-057716